>you point me in the direction of papers/books that explain how>debuggers work.

Although it is not a "learned" text, I suggest you take a
glance at the following book:

Ronald Mak
Writing Compilers & Interpreters
Wiley, 1991

This is a mass consumption book and comes with a disk of the
code. The author takes a very applied approach, dispensing
with the theory and concentrating on building software tools
which are central to the process. The tool-building approach
is what sets the book apart. Mak starts with simple scanning
tasks and works up thru various stages of gradually more
complex parsing, compiling, interpreting tasks. A summary
of the tasks taken from the preface is: